Ebay today announced it spent $75 million to buy StumbleUpon, a community-powered Web discovery service with approximately 2.3 million users.

EBay said StumbleUpon allows people to discover Web sites, people, videos, product information, communities and other online content based on personal interests. By allowing its community to rate the content, StumbleUpon gets smarter as its used, providing an increasing level of relevance over time.

"StumbleUpon's downloadable toolbar provides an engaging and unique experience to its users, but it is the similarities in our approaches to the concept of community that make it such a compelling addition to eBay," eBay senior director Michael Buhr said in a statement. EBay claimed StumbleUpon community grew 150 percent year over year and delivers approximately five million new recommendations a day to its users.

One use eBay might have for the StumbleUpon's Web site discovery technology is to re-purpose it into product recommendation technology similar to the kind ecommerce rival Amazon uses.

EBay said Buhr will become general manager of StumbleUpon, while the company's founders and management team will remain in their respective positions and will work with Buhr to enhance the user experience, evolve its unique product and grow the community.